This invention relates to the manufacture and construction of solar cell panels, and more particularly, to the encapsulation of solar cells interconnected in a multi-cell array.
Solar cell panels for directly converting radiant energy from the sun into electrical energy are well known. In order to support and protect the array of cells interconnected to form such a panel, common practice has been to laminate the array between preformed layers of silicone or other polymers backed by rigid glass or plastic sheets. The laminated sandwich so formed provides not only mechanical support for the array of cells, but also protects the cells from environmental degradation. The sandwich so formed is also useful in that it serves as a heat sink, conducting unwanted heat away from the cells.
A number of techniques have been commonly employed to improve the collection efficiency of solar cell arrays. Among these is the shingle-style interconnection of cells, wherein the electrical bus area on the face of one cell is disposed along an edge and is directly contacted to the bus on the rear of the next cell, in order to maximize the photosensitive area per unit area of panel in a series connected cell array. Because of the periodically varying thickness of such an array, it is not easily incorporated into a laminated structure, however. Not only may this result in inadequate encapsulation, with the attendant risk of environmental degradation of the poorly sealed-off cells, but also it should be noted that any voids between the cells and the front cover may result in a loss of efficiency due to reflection at the interfaces of the voids with the surrounding media. These voids will also lead to the poorer conduction of heat away from the cells.
Further, it should be noted that common assembly techniques often feature the rigid mounting of the cells of the array to a rigid substrate. Not only does this expose the cells to potential damage from mechanical shock transmitted through the substrate, but also places limitations on the size of tightly packed arrays if the stresses due to differential expansion between the array and the substrate are to be minimized.
Accordingly, one of the objects of the present invention is to provide an encapulated shingle-style solar cell array which is simple to fabricate and which does not contain deleterious voids, and which provides a resilient mounting of the cells, thereby minimizing mechanical and thermal problems.